This invention relates generally to medical devices and, in particular, to a handle for positioning thereinto the proximal end of a medical device for controlled movement with respect thereto.
Extractors or baskets have been used for the removal of stones and other foreign objects from the urinary or biliary system. Often, the distal portion of these devices consist of a series of wires or strips that can be manipulated by the handle and actuating wire to expand to form an open basket. By further manipulating the handle of the extractor, the target object is captured within the basket, and the device is withdrawn from the body.
The procedure for extraction of a kidney stone usually requires that an endoscope be introduced to locate the obstruction. Once the stone is visualized, the basket or extractor is introduced through an operating lumen in the scope to complete the procedure. Occasionally, the extractor with the stone are too large to be safely withdrawn and further instrumentation such as forceps or an ultrasonic wire must be introduced that aid in fragmenting the object for removal. Without an additional operating lumen through which these instruments may be introduced, the endoscope must be withdrawn over the extractor. To accomplish this, the handle of the extractor must first be removed.
Handles for many current extractors are end loaded with a hub or expanded portion at the proximal end of the actuating wires. The hubs locks into place with the handle mechanism. Unfortunately, however, they must be cut off the proximal end of the wire before the endoscope can be slid off the end of the extractor. This prevents reattachment and reuse of the handle to complete the procedure once the basket has been freed. The ideal handle for a stone extractor must be able to be removed on a temporary basis and be easily reattached without the loss of handle function.
One such handle for a stone extractor or retriever is disclosed in U.S. Pat. No. 6,053,934 issued to Andrews, et al., the disclosure of which is hereby incorporated by reference. The handle is disclosed for side loading the proximal end of a medical device therein, which is typically inserted within the operative lumen of an endoscope. The handle is easily removed from the proximal end of the medical device for removing the endoscope over the device. With the endoscope removed, the replaceable handle can side-load the proximal end of the device for added manipulation of the distal end such as in removing a stone from the kidney or ureter leading therefrom. Having an inner housing therewithin, the outer housing also includes a first attachment mechanism disposed about the distal end for receipt of the first device while the inner housing includes a second attachment mechanism in communication with an inner passageway for receipt of a second device adjacent to the first member. The outer housing also includes a projection positionable into the positioning channel of the inner elongated member to control longitudinal and rotational movement therebetween. The inner housing is longitudinally slidable in the handle passage when the projection is positioned in a longitudinal component of the positioning channel. The inner housing is also rotatable in the handle passage when the projection is positioned in a transverse or circumferential component of the positioning channel. Removing a stone with the retriever requires holding the inner housing firmly in the proximal-most position along the outer housing with one hand, while simultaneously pulling the retriever proximally from the patient with the other hand, or by another person assisting the procedure.
It is desired to provide a handle that facilitates manipulation of the inner device to perform a work step, such as grasping a stone prior to removal, by applying tension in only one direction needing only one hand.
It is also desired to provide a handle that enables easy removal and insertion of a medical device with respect to the handle.
The foregoing problems are solved and a technical advance is achieved in an illustrative replaceable or removable handle for a medical device that is typically inserted through the operating lumen of an endoscope, where the medical device includes an outer member and an inner member that is to be operable axially with respect to the outer member. The replaceable handle includes an outer elongated housing with a passage having external or lateral communication extending longitudinally at least partially therealong from the distal end thereof. The distal end portion of the handle assembly defines an arrangement for securing an outer member of the medical device against lateral and axial movement. The handle also includes an inner elongated housing positioned in the outer housing central passageway and preferably extending proximally therefrom and preferably having a positioning cam channel arrangement for cooperating with a cam follower of the outer housing, for advantageously controlling the longitudinal and the rotational or circumferential movement of the inner housing with respect to the outer housing. The inner housing also includes a locking arrangement disposed therein and communicating with an inner passageway for receipt therein of the inner medical device member in a manner that controls axial movement thereof and also is manually actuatable to release the inner member for removal from the handle assembly.
One aspect of the invention is a replaceable, medical device handle for loading the proximal end of a medical device including first and second coaxial members and for controlling relative axial movement of the first and second coaxial members. The replaceable, medical device handle comprises an outer elongated housing having a distal end, a passage extending longitudinally therealong and having external communication thereto, and also a first attachment mechanism associated with the outer elongated housing for attaching the outer elongated housing to one of the first and second coaxial members when the proximal end of the medical device is in the passage for constraining the one of the first and second coaxial members against axial movement relative to the outer elongated housing. The medical device also comprises an inner elongated member position in said passage and extending therealong supported for axial movement relative to the outer elongated housing, and a second attachment mechanism associated with the inner elongate member for attaching the inner elongate member to the other of the first and second coaxial members when the proximal end of the medical device is in the passage for constraining the other of the first and second coaxial members against axial movement relative to the inner elongated member. The outer housing and the inner member include a projection positionable in an associated channel arrangement to achieve relative rotational and longitudinal movement of the first and second device members. The medical device also includes a spring operably coupled between the outer elongated housing and the inner elongated member for biasing the outer elongated housing and the inner elongated member toward a particular relative longitudinal position.
In one aspect of the invention, the locking arrangement includes a push button that is depressible to align a wide slot portion with the inner passageway to permit the proximal end of the inner medical device member to be inserted therethrough; release of the push button permits the button to be biased outwardly to align a narrow slot portion with the inner passagway, thus trapping an enlarged end of the inner medical device member proximally of the push button and permitting manipulation of the inner housing of the handle to move the inner medical device member.
In another aspect, a slotted end cap is affixed at the distal end of the outer housing, and a slotted insert is positioned inwardly from the end cap, with the outer medical device member insertable through a wide slot entrance along the side of the outer housing to be disposed in and along the slots to be aligned with the inner passageway of the inner housing. Rotation of the inner housing at its proximal end in turn rotates the insert within the outer housing, which misaligns a narrow portion of the slot of the insert with respect to the narrow slot of the end cap, thus trapping the outer medical device member against lateral movement, while the misaligning of the slots also defines stops for the outer medical device member against axial movement thereof when larger diameter portions thereof outside of the slots abut orthogonal faces of the end cap and insert at ends of the narrow slots.
In a further aspect of the present invention, the handle assembly includes a biasing arrangement to urge the inner housing proximally with respect to the outer housing, and thus urge the inner medical device member proximally with respect to the outer medical device member. This enables the inner member to be biased proximally with respect to the outer member without manual assistance. Where the medical device is a stone retriever, after the stone is captured by a stone basket of an inner control rod, the stone is securely held during withdrawal of the medical device from the patient without manual assistance to maintain the inner control rod biased proximally with respect to the outer cannula, thus allowing stone retrieval using only one hand to generally hold the handle assembly.